Study of the properties of hard and soft particle production as a function of particle multiplicity in p-p collisions at √s = 7 TeV

Abstract

The characteristics of multi-particle production in p-p collisions at √s = 7 TeV are studied as a function of the event charged particle multiplicity (Nch), by classifying the measured tracks into two distinct classes, those belonging to jets and those belonging to the underlying event (UE). Charged tracks are measured within pseudorapidity |η| <2.4 above transverse momenta pT = 0.25 GeV/c and charged-particle jets are reconstructed above pT = 5 GeV/c with track-only information. The distributions of jet pT, average pT of UE tracks and jets, jet rates, and jet shapes are studied as a function of Nch and are compared to the predictions of the PYTHIA and HERWIG Monte Carlo (MC) event generators. As the event-multiplicity increases, PYTHIA systematically predicts higher jet rates and harder pT spectra than seen in the data, whereas HERWIG shows the opposite trend. In the lowest-multiplicity events, the data show narrower jets than predicted by both MC generators.

Figures

  Figure 1

Figure 1. Event topology: small colored rectangles represent charged particles; semitransparent grey areas cover charged particles belonging to jets .

  Figure 2
Figure 2. Dependence of pT spectrum of the charged-particles of the underlying event on the radius of the jet-defining cones.

  Figure 3
Figure 3. Charged particle multiplicity distributions for all the multiplicity bins measured in the data and compared to four MC predictions.

  Figure 4
Figure 4. Mean transverse momentum of inclusive charged tracks with pT > 0.25 GeV/c versus the corrected p-p charged-particle multiplicity (Nch within |η|<2.4), full events in p-p collisions at 7 TeV.

  Figure 5
Figure 5. Mean transverse momentum of UE charged tracks with pT > 0.25 GeV/c versus corrected charged-particle multiplicity (Nch within |η|<2.4) in p-p collisions at 7 TeV.

  Figure 6
Figure 6. Mean transverse momentum of intrajet charged tracks with pT > 0.25 GeV/c versus charged-particle multiplicity (Nch within |η|<2.4) in p-p collisions at 7 TeV.

  Figure 8
Figure 7. Mean transverse momentum of leading intrajet charged tracks with pT > 0.25 GeV/c versus charged-particle multiplicity (Nch within|η|<2.4) in p-p collisions at 7 TeV.

  Figure 8
Figure 8. Number of charged-particle jets per event for threshold pTch.jet</em > 5 GeV/c and axes within |η|< 1.9 versus charged-particle multiplicity Nch (within |η|<2.4) in p-p collisions at 7 TeV.

  Figure 9
Figure 9. Number of charged-particle jets per event for threshold pTch.jet</em > 30 GeV/c and axes within |η|< 1.9 versus charged-particle multiplicity Nch (within |η|<2.4) in p-p collisions at 7 TeV.

  Figure 10
Figure 10. Mean transverse momentum of charged-particle jets (with pTch.jet</em >>5 GeV/c and axes within |η|< 1.9) versus charged-particle multiplicity (Nch (within |η|<2.4) in p-p collisions at 7 TeV.

  Figure 11
Figure 11. Inclusive charged-particle jet pT spectrum in the charged-particle multiplicity domain 10 <Nch < 30 in p-p collisions at 7 TeV.

  Figure 12
Figure 12. Inclusive charged-particle jet pT spectrum in the charged-particle multiplicity domain 30 <Nch < 50 in p-p collisions at 7 TeV.

  Figure 13
Figure 13. Inclusive charged-particle jet pT spectrum in the charged-particle multiplicity domain 50 <Nch < 80 in p-p collisions at 7 TeV.

  Figure 14
Figure 14. Inclusive charged-particle jet pT spectrum in the charged-particle multiplicity domain 80 <Nch < 110 in p-p collisions at 7 TeV.

  Figure 15
Figure 15.Inclusive charged-particle jet pT spectrum in the charged-particle multiplicity domain 110 <Nch < 140 in p-p collisions at 7 TeV.

  Figure 16
Figure 16. Charged-particle jet pT density in ring zones as a function of distance to the jet axis, R, in the charged-particle multiplicity domain 10 <Nch < 30 in p-p collisions at 7 TeV.

  Figure 17
Figure 17. Charged-particle jet pT density in ring zones as a function of distance to the jet axis, R, in the charged-particle multiplicity domain 30 <Nch < 50 in p-p collisions at 7 TeV.

  Figure 18
Figure 18. Charged-particle jet pT density in ring zones as a function of distance to the jet axis, R, in the charged-particle multiplicity domain 50 <Nch < 80 in p-p collisions at 7 TeV.

  Figure 19
Figure 19. Charged-particle jet pT density in ring zones as a function of distance to the jet axis, R, in the charged-particle multiplicity domain 80 <Nch < 110 in p-p collisions at 7 TeV.

  Figure 20
Figure 20. Charged-particle jet pT density in ring zones as a function of distance to the jet axis, R, in the charged-particle multiplicity domain 110 <Nch < 140 in p-p collisions at 7 TeV.
Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng EventTopology.png r2 r1 manage 22.8 K 2013-04-16 - 20:13 MaksimAzarkin  
PNGpng JetMeanPt_vs_mult.png r1 manage 248.8 K 2014-09-15 - 07:10 MaksimAzarkin  
PNGpng JetRate_30GeV.png r1 manage 248.9 K 2014-09-15 - 07:10 MaksimAzarkin  
PNGpng JetRate_5GeV.png r1 manage 229.4 K 2014-09-15 - 07:10 MaksimAzarkin  
PNGpng JetStruct_10-30.png r1 manage 202.1 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng JetStruct_110-140.png r1 manage 181.2 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng JetStruct_30-50.png r1 manage 202.9 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng JetStruct_50-80.png r1 manage 205.5 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng JetStruct_80-110.png r1 manage 181.7 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng MultDistributions.png r1 manage 341.4 K 2014-09-15 - 07:10 MaksimAzarkin  
PNGpng cone_radii.png r1 manage 36.0 K 2013-04-16 - 20:41 MaksimAzarkin  
PNGpng global_spectrum_vs_mult.png r1 manage 249.9 K 2014-09-15 - 07:10 MaksimAzarkin  
PNGpng intrajet_leader_spectrum_vs_mult.png r1 manage 255.9 K 2014-09-15 - 07:10 MaksimAzarkin  
PNGpng intrajet_spectrum_vs_mult.png r1 manage 260.2 K 2014-09-15 - 07:10 MaksimAzarkin  
PNGpng jet_spectrum_njet_10-30.png r1 manage 240.2 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng jet_spectrum_njet_110-140.png r1 manage 232.3 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng jet_spectrum_njet_30-50.png r1 manage 240.7 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng jet_spectrum_njet_50-80.png r1 manage 239.9 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng jet_spectrum_njet_80-110.png r1 manage 228.8 K 2014-09-15 - 07:05 MaksimAzarkin  
PNGpng soft_spectrum_vs_mult.png r1 manage 267.9 K 2014-09-15 - 07:10 MaksimAzarkin  
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Topic revision: r8 - 2014-09-15 - MaksimAzarkin
 
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